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40Race Shoe FinderEst. 2023 · London

Head to head

Nike Alphafly 3vs
On Cloudboom Strike

Alphafly 3

£203

Typical street price · £285 RRP

40mm — on the limit
Cloudboom Strike

£175

Typical street price · £270 RRP

39mm — road legal

Choose the Alphafly 3 if…

  • You want the bigger return: 3.4–4.6% economy gain against 3–4.2%, and that gap widens the longer you are out there.
  • You want a conventional fit rather than a narrow or wide last.
  • You would rather buy on measured numbers: this shoe's specs are manufacturer-confirmed, the Cloudboom Strike's are estimated.

Choose the Cloudboom Strike if…

  • You want the lighter shoe: 195g against 218g, a 23g difference you will feel late in a race.
  • You have a narrow foot and want to be locked in.

What does this
mean for you?

Every figure below is recalculated from your race and your current time. The gap between two shoes is not fixed — it grows with how long you are on your feet.

Over marathon from 3:45:00

Time back
Alphafly 3: 179s–260sCloudboom Strike: 152s–233s
Cost per second saved
Alphafly 3: £0.23Cloudboom Strike: £0.23

Ranges, not promises. Both figures are against a standard trainer, and the honest answer for most runners is that the difference between two shoes of this class is smaller than the difference a month of decent training makes.

Every number.

010203040504032
Alphafly 3
010203040503933
Cloudboom Strike

What you pay

Street price
Alphafly 3£203
Cloudboom Strike£175■

What the shoe is actually selling for across the shops we read, not its RRP.

RRP
Alphafly 3£285
Cloudboom Strike£270

List price. Almost nobody pays it for a race shoe.

Cost per race
Alphafly 3£51
Cloudboom Strike£44■

Street price divided by the races the foam stays fast for.

Cost per second saved
Alphafly 3£0.23
Cloudboom Strike£0.23■

The whole-life question: what each second of race time costs you.

What it does

Estimated saving
Alphafly 3179s–260s■
Cloudboom Strike152s–233s

Against a standard trainer, over the distance and time set above.

Economy gain
Alphafly 33.4–4.6%■
Cloudboom Strike3–4.2%
Built for
Alphafly 3Half · Marathon
Cloudboom StrikeHalf · Marathon
Best use case
Alphafly 3Still the reference marathon shoe. The Air pods give a propulsive forefoot that nothing else quite replicates, and the wider platform makes it manageable late in a race when your form has gone.
Cloudboom StrikeA genuinely competitive marathon racer and the first On shoe that belongs in this conversation on merit.

How it is built

Weight
Alphafly 3218 g
Cloudboom Strike195 g■

Manufacturer figure at men's US 9.

Stack (heel)
Alphafly 340 mm
Cloudboom Strike39 mm
Stack (forefoot)
Alphafly 332 mm
Cloudboom Strike33 mm
Drop
Alphafly 38 mm
Cloudboom Strike6 mm
Foam
Alphafly 3ZoomX with Air Zoom pods
Cloudboom StrikeHelion HF
Plate
Alphafly 3carbon fibre
Cloudboom Strikecarbon fibre

Rules and fit

Road legal
Alphafly 3Yes (40 mm)
Cloudboom StrikeYes (39 mm)

World Athletics caps road racing shoes at 40 mm of stack.

Fit
Alphafly 3standard
Cloudboom Strikenarrow
Stability
Alphafly 3balanced
Cloudboom Strikebalanced

Neither is better in the abstract — it depends on your stride.

Race life
Alphafly 3~250 km
Cloudboom Strike~250 km

How long the foam stays fast, not how long the shoe survives.

Data confidence
Alphafly 3verified■
Cloudboom Strikeestimated

■ marks the better figure where one is genuinely better. Fit, foam, drop and stability carry no mark — they depend on your foot and your stride, not on which shoe is superior.

In your size.

Where to buy

Your UK size

Best price today — some sizes£199.99at Run North West — £85 under RRP

9 retailer checks failed on the last run, so their prices are missing rather than wrong.

Prices are captured when the site is built and stamped with the time of that check. We never rank a retailer by what it pays us; where a link earns a commission it is marked sponsored and the price you pay is unchanged.

Where to buy

Your UK size

Best price today — some sizes£175at Fitstuff — £95 under RRP

9 retailer checks failed on the last run, so their prices are missing rather than wrong.

Prices are captured when the site is built and stamped with the time of that check. We never rank a retailer by what it pays us; where a link earns a commission it is marked sponsored and the price you pay is unchanged.